Comparing periodontitis biomarkers in saliva, oral rinse and gingival crevicular fluid: A pilot study

Association between metabolic syndrome and salivary MMP-8, myeloperoxidase in periodontitis

OBJECTIVE

This study investigated the effect of metabolic syndrome (MetS) on periodontal clinical parameters and salivary biomarkers' matrix metalloproteinase-8 (MMP-8) and myeloperoxidase (MPO) in patients with periodontitis.

METHODS

A total of 120 participants aged 25-55 were categorized into three groups: MetS with periodontitis (n = 40); systemically healthy with periodontitis (n = 40); and systemically and periodontally healthy controls (n = 40). Data collected included systemic parameters like waist circumference (WC), blood pressure (BP), high- and low-density lipoproteins, triglycerides (TG), fasting blood sugar (FBS), and glycated hemoglobin (HbA1c). Periodontal parameters estimated included bleeding on probing score (BoP), full-mouth plaque score (FMPS), periodontal probing depth (PPD), clinical attachment loss (CAL), and the number of missing teeth. Unstimulated whole saliva was analyzed via ELISA for active MMP-8 (aMMP-8), total MMP-8 (tMMP-8), and MPO.

RESULTS

Participants with MetS and periodontitis exhibited significantly higher periodontal parameters, salivary aMMP-8, and MPO (26.26 vs. 24.1 ng/mL and 13.53 vs. 11.55 ng/mL compared to systemically healthy periodontitis patients) (all p < 0.01). Positive correlations occurred between aMMP-8 and WC, TG, and FBS (p < 0.01), and between MPO and WC, BP, and TG (p < 0.01).

CONCLUSIONS

The positive associations between these biomarkers and metabolic parameters indicate their potential utility for monitoring cardiovascular and glycemic risk in patients with periodontal disease.

High-Throughput Combined Analysis of Saliva Microbiota and Metabolomic Profile in Chinese Periodontitis Patients: A Pilot Study

The onset and progression of periodontitis involves complicated interactions between the dysbiotic oral microbiota and disrupted host immune-inflammatory response, which can be mirrored by the changes in salivary metabolites profile. This pilot study sought to examine the saliva microbiome and metabolome in the Chinese population by the combined approach of 16s rRNA sequencing and high-throughput targeted metabolomics to discover potential cues for host-microbe metabolic interactions. Unstimulated whole saliva samples were collected from eighteen Stage III and IV periodontitis patients and thirteen healthy subjects. Full-mouth periodontal parameters were recorded. The taxonomic composition of microbiota was obtained by 16s rRNA sequencing, and the metabolites were identified and measured by ultra-high performance liquid chromatography and mass spectrometry-based metabolomic analysis. The oral microbiota composition displayed marked changes where the abundance of 93 microbial taxa differed significantly between the periodontitis and healthy group. Targeted metabolomics identified 103 differential metabolites between the patients and healthy individuals. Functional enrichment analysis demonstrated the upregulation of protein digestion and absorption, histidine metabolism, and nicotinate and nicotinamide metabolism pathways in the dysbiotic microbiota, while the ferroptosis, tryptophan metabolism, glutathione metabolism, and carbon metabolism pathways were upregulated in the patients. Correlation analysis confirmed positive relationships between the clinical parameters, pathogen abundances, and disease-related metabolite levels. The integral analysis of the saliva microbiome and metabolome yielded an accurate presentation of the dysbiotic oral microbiome and functional alterations in host-microbe metabolism. The microbial and metabolic profiling of the saliva could be a potential tool in the diagnosis, prognosis evaluation, and pathogenesis study of periodontitis.

Preventive and Therapeutic Potential of Streptococcus cristatus CA119 in Experimental Periodontitis in Rats

Periodontitis is an inflammatory condition of the oral cavity caused by a mixed infection of various bacteria, which not only severely affects the alveolar bone and connective tissues but also displays potential correlations with distal intestinal inflammation. In this study, we aimed to elucidate the therapeutic effects of Streptococcus cristatus CA119 on experimental periodontitis in rats and its impact on intestinal morphology. The results demonstrate that CA119 is capable of colonizing the oral cavity and exerting antagonistic effects on Porphyromonas gingivalis and Fusobacterium nucleatum, thus leading to a significant reduction in the oral pathogen load. Following CA119 intervention, there was a significant alleviation of weight loss in rats induced by periodontitis (P < 0.001). CA119 also regulated the expression of IL-6 (P < 0.05), IL-1β (P < 0.001), IL-18 (P < 0.001), COX-2 (P < 0.001), iNOS (P < 0.001), and MCP-1 (P < 0.01) in the gingival tissue. Additionally, CA119 reduced oxidative stress levels in rats and enhanced their antioxidant capacity. Microcomputed tomography (micro-CT) and histological analysis revealed that CA119 significantly reduced alveolar bone loss and reversed the downregulation of OPG/RANKL (P < 0.001). Furthermore, CA119 exhibited a significant protective effect against intestinal inflammation induced by periodontal disease and improved the colonic morphology in rats. In conclusion, this study demonstrates the role of CA119 as a potential oral probiotic in the prevention and treatment of experimental periodontitis, underscoring the potential of probiotics as a complementary approach to traditional periodontal care.

The impact of saliva collection methods on measured salivary biomarker levels

Saliva diagnostics have become increasingly popular due to their non-invasive nature and patient-friendly collection process. Various collection methods are available, yet these are not always well standardized for either quantitative or qualitative analysis. In line, the objective of this study was to evaluate if measured levels of various biomarkers in the saliva of healthy individuals were affected by three distinct saliva collection methods: 1) unstimulated saliva, 2) chew stimulated saliva, and 3) oral rinse. Saliva samples from 30 healthy individuals were obtained by the three collection methods. Then, the levels of various salivary biomarkers such as proteins and ions were determined. It was found that levels of various biomarkers obtained from unstimulated saliva were comparable to those in chew stimulated saliva. The levels of potassium, sodium, and amylase activity differed significantly among the three collection methods. Levels of all biomarkers measured using the oral rinse method significantly differed from those obtained from unstimulated and chew-stimulated saliva. In conclusion, both unstimulated and chew-stimulated saliva provided comparable levels for a diverse group of biomarkers. However, the results obtained from the oral rinse method significantly differed from those of unstimulated and chew-stimulated saliva, due to the diluted nature of the saliva extract.

Probiotics Partly Suppress the Impact of Sugar Stress on the Oral Microbiota-A Randomized, Double-Blinded, Placebo-Controlled Trial

The aim was to test if probiotics counteract oral dysbiosis during 14 days of sugar stress and subsequently help restore oral homeostasis. Eighty healthy individuals received either probiotics (n = 40) or placebo lozenges (n = 40) for 28 days and rinsed with a 10% sucrose solution 6-8 times during the initial 14 days of the trial. Saliva and supragingival samples were collected at baseline, day 14, and day 28. Saliva samples were analyzed for levels of pro-inflammatory cytokines, albumin, and salivary enzyme activity. The supragingival microbiota was characterized according to the Human Oral Microbiome Database. After 14 days of sugar stress, the relative abundance of Porphyromonas species was significantly higher (p = 0.03) and remained significantly elevated at day 28 in the probiotic group compared to the placebo group (p = 0.004). At day 28, the relative abundance of Kingella species was significantly higher in the probiotic group (p = 0.03). Streptococcus gordinii and Neisseria elongata were associated with the probiotic group on day 28, while Streptococcus sobrinus was associated with the placebo group on day 14 and day 28. On day 28, the salivary albumin level was significantly lower in the probiotic group. The present study demonstrates a potential stabilizing effect on the supragingival microbiota mediated by consumption of probiotics during short-term sugar stress.

Probiotics Support Resilience of the Oral Microbiota during Resolution after Experimental Gingivitis-A Randomized, Double-Blinded, Placebo-Controlled Trial

The present study aims to test whether probiotics protect against experimental gingivitis incited by 14 days of oral hygiene neglect and/or subsequently support the restoration of oral homeostasis. Eighty systemically and orally healthy participants refrained from oral hygiene procedures for 14 days, followed by 14 days with regular oral hygiene procedures. Additionally, participants consumed either probiotics (n = 40) or placebo (n = 40) throughout the trial. At baseline, day 14, and day 28, supragingival plaque score and bleeding-on-probing percentage (BOP %) were registered, and supragingival plaque and saliva samples were collected. The supragingival microbiota was characterized using 16S sequencing, and saliva samples were analyzed for levels of pro-inflammatory cytokines and proteases. At day 28, the relative abundance of Lautropia (p = 0.014), Prevotella (p = 0.046), Fusobacterium (p = 0.033), and Selenomonas (p = 0.0078) genera were significantly higher in the placebo group compared to the probiotics group, while the relative abundance of Rothia (p = 0.047) species was associated with the probiotics group. Streptococcus sanguinis was associated with the probiotics group, while Campylobacter gracilis was associated with the placebo group. No difference was observed in salivary cytokines, albumin, or any enzyme activity. The present study suggests that probiotics support the resilience of the oral microbiota in the resolution period after gingivitis.

Active Matrix Metalloproteinase-8 (aMMP-8) Versus Total MMP-8 in Periodontal and Peri-Implant Disease Point-of-Care Diagnostics

Active matrix metalloproteinase-8 (aMMP-8) is a promising biomarker candidate for the modern periodontal and peri-implant disease diagnostics utilizing the chairside/point-of-care oral fluid technologies. These rapid biomarker analysis technologies utilize gingival crevicular fluid (GCF), peri-implant sulcular fluid (PISF), or mouth rinse as the oral fluid matrices that can be collected patient-friendly and non-invasively without causing bacteremia. aMMP-8, but not total or latent proMMP-8, has been shown to be a relevant biomarker to be implemented to the latest 2017 classification system of periodontitis and peri-implantitis. Thus, aMMP-8 point-of-care-testing (POCT)-but not total or latent proMMP-8-can be conveniently used as an adjunctive and preventive diagnostic tool to identify and screen the developing and ongoing periodontal and peri-implant breakdown and disease as well as predict its episodic progression. Similarly, aMMP-8 POCT provides an important tool to monitor the treatment effect of these diseases, but also other diseases such as head and neck cancer, where it can identify and predict the rapid tissue destructive oral side-effects during and after the radiotherapy. Additionally, recent studies support aMMP-8 POCT benefitting the identification of periodontitis and diabetes as the escalating risk diseases for COVID-19 infection. Overall, aMMP-8 POCT has launched a new clinical field in oral medicine and dentistry, i.e., oral clinical chemistry.

Macrophages induce gingival destruction via Piezo1-mediated MMPs-degrading collagens in periodontitis

Macrophages are an integral part of the innate immune response in periodontal tissue and play a crucial role in the progression of periodontitis. Here we reported that macrophages also provoke periodontitis-induced gingival destruction through Piezol-mediated collagen degradation. We discovered that the PIEZO1 expression was markedly elevated in patients with periodontitis through transcriptomic profiling. Moreover, Piezo1 promoted macrophage polarization toward the M1 type in response to lipopolysaccharide (LPS) and induced production of proinflammatory cytokines, which in turn stimulated production of matrix metalloproteinases (MMPs) leading to collagen degradation. Our study suggests that Piezol might be a potential therapeutic target for treating periodontitis-induced gingival destruction.

Neutrophils in the periodontium: Interactions with pathogens and roles in tissue homeostasis and inflammation

Neutrophils are of key importance in periodontal health and disease. In their absence or when they are functionally defective, as occurs in certain congenital disorders, affected individuals develop severe forms of periodontitis in early age. These observations imply that the presence of immune-competent neutrophils is essential to homeostasis. However, the presence of supernumerary or hyper-responsive neutrophils, either because of systemic priming or innate immune training, leads to imbalanced host-microbe interactions in the periodontium that culminate in dysbiosis and inflammatory tissue breakdown. These disease-provoking imbalanced interactions are further exacerbated by periodontal pathogens capable of subverting neutrophil responses to their microbial community's benefit and the host's detriment. This review attempts a synthesis of these findings for an integrated view of the neutrophils' ambivalent role in periodontal disease and, moreover, discusses how some of these concepts underpin the development of novel therapeutic approaches to treat periodontal disease.

Diagnostic accuracy of active matrix metalloproteinase-8 point-of-care test for the discrimination of periodontal health status: Comparison of saliva and oral rinse samples

BACKGROUND AND OBJECTIVES

Assessment of biomarkers, specifically active matrix metalloproteinase-8 (aMMP-8), in saliva/oral rinses is a promising diagnostic approach for periodontal health and disease. Different oral fluids have specific advantages and limitations. This study investigates the effect of sampling different fluids on the accuracy of an aMMP-8 point of care test (POCT).

METHODS

Unstimulated whole saliva, a first, and a second oral rinse were sequentially taken from 95 consecutive adults. aMMP-8 was quantitatively determined with a lateral flow immunoassay (index test). A full-mouth periodontal examination was used to establish a diagnosis according to the 2017 World Workshop classification of periodontal diseases (reference standard). Diagnostic measures of the area under the receiver operating characteristic curve (AUROC), sensitivity, and specificity were assessed and compared.

RESULTS

In all oral fluid samples, periodontitis patients (N = 61) had significantly elevated aMMP-8 levels and increased test positivity rates compared with subjects with periodontal health or gingivitis (N = 34). The intra-individual comparison showed that aMMP-8 levels were significantly higher in 1st oral rinse compared with other samples (1^st oral rinse > saliva = 2^nd oral rinse, p = .007). The aMMP-8 test using 1st oral rinse exhibited the best accuracy for detecting periodontitis with a sensitivity of 80.3%, a specificity of 67.8% and an AUROC of 0.740.

CONCLUSIONS

A 30-second oral rinse with water omitting the prerinse provided the best accuracy to discriminate periodontal health and disease with an aMMP-8 POCT. This regimen seems promising for further studies in large representative populations to verify the current findings.

Salivary Enzymatic Activity and Carious Experience in Children: A Cross-Sectional Study

Salivary biomolecules are considered important modulators of the oral microflora, with a potential subsequent impact on dental health. The present study aimed to investigate the relationship between salivary enzymatic activity and carious experience in children. The carious experience of a sample of 22 school children was evaluated by calculating dmf/DMF indices, following WHO recommendations. Unstimulated whole saliva was collected, and salivary alpha-amylase levels, total protease activity, and matrix metalloproteinase levels (MMP-8 and MMP-9) were measured. The data were analyzed using parametric and nonparametric tests. Our findings revealed no significant relationship between the investigated salivary parameters and the carious experience in permanent teeth (DMFT/DMFS scores). Carious indices scores for primary teeth (dmft and dmfs) were positively associated with MMP-8 levels (r = 0.62, p = 0.004 and r_s = 0.61, p = 0.006, respectively) and MMP-9 levels (r = 0.45, p = 0.05 and r_s = 0.48, p = 0.039, respectively) and negatively associated with alpha-amylase levels (r_s = −0.54, p = 0.017 and r_s = −0.59, p = 0.006, respectively). Although with a marginal significance, PEK−054 levels positively correlated with dental caries, while for PFU−089, a negative correlation was observed. These results suggest that salivary alpha-amylase and MMP-8 and MMP-9 levels may be considered potential indicators of carious experience in children. Further studies with a prospective design are needed in order to elucidate the role of these biomolecules in caries development.

Phase 2a clinical trial of complement C3 inhibitor AMY-101 in adults with periodontal inflammation

BACKGROUND

Gingivitis and periodontitis are prevalent inflammatory diseases of the periodontal tissues. Current treatments are often ineffective or do not prevent disease recurrence. Uncontrolled complement activation and resulting chronic gingival inflammation is a hallmark of periodontal diseases. We determined efficacy and safety of a complement 3-targeted therapeutic, AMY-101, locally administered in adults with periodontal inflammation.

METHODS

Thirty-two patients with gingival inflammation were enrolled into a randomized, placebo-controlled, double-blind, split-mouth design phase 2a trial, after dose-escalation study to select safe and effective dose with additional 8 patients. Half of the mouth was randomly assigned to AMY-101 (0.1mg/site) or placebo injections at sites of inflammation, administered on days 0, 7 and 14 and evaluated for safety and efficacy outcomes at days 28, 60 and 90. The primary efficacy outcome was change in gingival inflammation, measured by modified gingival index (MGI), and secondary outcomes included changes in bleeding-on-probing (BOP), amount of plaque, pocket depth, clinical attachment level, and gingival crevicular fluid levels of matrix metalloproteinases (MMPs) over 90 days.

RESULTS

A once-per-week intragingival injection of AMY-101 for 3 weeks was safe and well-tolerated in all participants resulting in significant (P<0.001) reductions in clinical indices measuring gingival inflammation (MGI and BOP). AMY-101 significantly (P<0.05) reduced MMP-8 and MMP-9 levels, indicators of inflammatory tissue destruction. These therapeutic effects persisted for at least 3 months post-treatment.

CONCLUSION

AMY-101 causes significant and sustainable reduction in gingival inflammation without adverse events and merits further investigation for the treatment of periodontitis and other oral or peri-implant inflammatory conditions.

TRIAL REGISTRATION

ClinicalTrials.gov: NCT03694444.

FUNDING

Amyndas Pharmaceuticals. Amyndas contributed to the design and conducts of the clinical trial and in the writing of the manuscript.